Abstract: A permanent magnet, DC motor especially well adapted for use in power tools, and particularly hand-held, battery powered power tools. The motor includes two sets of armature coils, with each set of coils being coupled to separate sets of commutator bars on an armature. Separate pairs of brushes are used to interface with the two sets of commutator bars. A switching subsystem is controlled either manually by a user engageable switch or automatically by a controller, to connect the two sets of coils in either series or parallel configurations. The series configuration provides a greater efficiency, but with a lower power output than the parallel connection. The parallel connection provides a greater maximum power output from the motor. Thus, the operating characteristics of the tool can be tailored to better meet the needs of a work task, and in a manner than makes most efficient use of available battery power.

Abstract: A power tool may include an electronically commutated motor such as, for example, a brushless DC permanent magnet motor with a rotor having internally mounted magnets and/or cavities filled with air or other non-magnetic materials. A control system may be used to control the motor in a manner that implements field weakening when the speed of the motor increases beyond its rated motor speed, or when the torque demands on the motor continue to increase after the maximum power output of the motor is reached. The field weakening may offset the growing back EMF and may enable a constant power and constant efficiency to be achieved by the motor over a wide speed range, rather than at just a single predetermined operating speed. Pulse width modulation control of the motor may be used up until the motor reaches its maximum power output.

Abstract: A sander may include a wand having a proximal end and a distal end, a sanding head mounted to the proximal end of the wand, and a brushless motor mounted on the distal end of the wand that is configured to provide rotational motion to the sanding head.

Abstract: A power tool having an electronically commutated DC motor capable of providing various operating modes ranging from a maximum efficiency operating mode to a maximum power operating mode. The motor has a rotor having permanent magnets mounted in recesses in a back iron of the rotor. In one embodiment the motor has three phase windings, each having at least a pair of coils. The phase windings are connected in either a delta or a wye configuration via electromechanical or electronic switching components, or a combination of both, by a controller within the tool. The coils in each phase winding can also be switched between series and parallel configurations to configure the motor to provide its various operating modes. In one embodiment a dual wound motor is disclosed that has its phase coils dynamically or statically switchable between series and parallel configurations.

Abstract: A permanent magnet, DC motor especially well adapted for use in power tools, and particularly hand-held, battery powered power tools. The motor includes two sets of armature coils, with each set of coils being coupled to separate sets of commutator bars on an armature. Separate pairs of brushes are used to interface with the two sets of commutator bars. A switching subsystem is controlled either manually by a user engageable switch or automatically by a controller, to connect the two sets of coils in either series or parallel configurations. The series configuration provides a greater efficiency, but with a lower power output than the parallel connection. The parallel connection provides a greater maximum power output from the motor. Thus, the operating characteristics of the tool can be tailored to better meet the needs of a work task, and in a manner than makes most efficient use of available battery power.

Abstract: A hand held orbital sander has a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing. A motor controller is coupled to the motor. The motor controller changes the speed of at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changes the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value. The sander may have a mechanical brake that brakes the orbit mechanism and the motor controller also dynamically brakes the motor.

Abstract: A power tool is a “low profile” power tool, that is the overall height of the power tool is sufficiently small that a user can grasp the top of the power tool with the user's hand and the hand will be positioned relative close to the bottom of the power tool compared with existing power tools. The low profile power tool uses a low profile motor having a diameter to lamination height ratio of at least 2:1. In an aspect of the invention, the motor is an electronically commutated “pancake” style motor. In an aspect of the invention, the power tool is a random orbital sander or an orbital sander having a motor that provides at least 40 watts of power. In an aspect of the invention, the sander has a mechanical brake that brakes the orbital mechanism and the motor is dynamically braked.

Abstract: A power tool may include an electronically commutated motor such as, for example, a brushless DC permanent magnet motor with a rotor having internally mounted magnets and/or cavities filled with air or other non-magnetic materials. A control system may be used to control the motor in a manner that implements field weakening when the speed of the motor increases beyond its rated motor speed, or when the torque demands on the motor continue to increase after the maximum power output of the motor is reached. The field weakening may offset the growing back EMF and may enable a constant power and constant efficiency to be achieved by the motor over a wide speed range, rather than at just a single predetermined operating speed. Pulse width modulation control of the motor may be used up until the motor reaches its maximum power output.

Abstract: A hand held orbital sander has a housing having an electronically commutated motor disposed therein and an orbit mechanism disposed beneath the housing. A motor controller is coupled to the motor. The motor controller changes the speed of at which it runs the motor from an idle speed to a sanding speed upon the motor speed dropping from idle speed to an idle speed threshold value and changes the speed at which it runs the motor from sanding speed to idle speed upon the motor speed increasing from sanding speed to a sanding speed threshold value. The sander may have a mechanical brake that brakes the orbit mechanism and the motor controller also dynamically brakes the motor.